II-6 TROUBLESHOOTING
DIAGhUSTIC PROCEDURES
Gasoline Engines
1. Engine turns over, but wilt not start
a. Check fuel level in fuel tank, add fuel if empty.
b. Check battery condition and state of charge. If voltage and load test below specifica-
tion, charge or replace battery.
c. Check battery terminal and cable condition and tightness. Clean terminals and replace
damaged, worn or corroded cables.
d. Check fuel delivery system. If fuel is not reaching the fuel injectors, check for a loose
electrical connector or defective fuse, relay or fuel pump and replace as necessary.
e. Engine may have excessive wear or mechanical damage such as low cylinder cranking
pressure, a broken camshaft drive system, insufficient valve clearance or bent valves.
f. Check for fuel contamination such as water in the fuel. During winter months, the wa-
ter may freeze and cause a fuel restriction. Adding a fuel additive may help, however
the fuel system may require draining and purging with fresh fuel.
g. Check for ignition system failure. Check for loose or shorted wires or damaged igni-
tion system components. Check the spark plugs for excessive wear or incorrect elec-
trode gap. If the problem is worse in wet weather, check for shorts between the spark
plugs and the ignition coils.
h. Check the engine management system for a failed sensor or control module.
2. Engine does not turn over when attempting to start
a. Check the battery state of charge and condition. If the dash lights are not visible or
very dim when turning the ignition key on, the battery has either failed internally or
discharged, the battery cables are loose, excessively corroded or damaged, or the al-
ternator has failed or internally shorted, discharging the battery. Charge or replacethe
battery, clean or replace the battery cables, and check the alternator output.
b. Check the operation of the neutral safety switch. On automatic transmission vehicles,
try starting the vehicle in both Park and Neutral. On manual transmission vehicles, de-
press the clutch pedal and attempt to start. On some vehicles, these switches can be
adjusted. Make sure the switches or wire connectors are not loose or damaged. Re-
place or adjust the switches as necessary.
c. Check the starter motor, starter solenoid or relay, and starter motor cables and wires.
Check the ground from the engine to the chassis. Make sure the wires are not loose,
damaged, or corroded. If battery voltage is present at the starter relay, try using a re-
mote starter to start the vehicle for test purposes only. Replace any damaged or cor-
roded cables, in addition to replacing any failed components.
d. Check the engine for seizure. If the engine has not been started for a long period of
time, internal parts such as the rings may have rusted to the cylinder walls. The engine
may have suffered internal damage, or could be hydro-locked from ingesting water.
Remove the spark plugs and carefully attempt to rotate the engine using a suitable
breaker bar and socket on the crankshaft pulley. If the engine is resistant to moving, or
moves slightly and then binds, do not force the engine any further before determining
the problem.
3. Enpine stalls immediately when started
a. Check the ignition switch condition and operation. The electrical contacts in the run
position may be worn or damaged. Try restarting the engine with all electrical acces-
sories in the off position. Sometimes turning the key on an off will help in emergency
situations, however once the switch has shown signs of failure, it should be replaced
as soon as possible.
b. Check for loose, corroded, damaged or shorted wires for the ignition system and re-
pair or replace.
c. Check for manifold vacuum leaks or vacuum hose leakage and repair or replace parts
as necessary.
d. Measure the fuel pump delivery volume and pressure. Low fuel pump pressure can
also be noticed as a lack of power when accelerating. Make sure the fuel pump lines
are not restricted. The fuel pump output is not adjustable and requires fuel pump re-
placement to repair.
e. Check the engine fuel and ignition management system. Inspect the sensor wiring and
electrical connectors. A dirty, loose or damaged sensor or control module wire can
simulate a failed component.
f. Check the exhaust system for internal restrictions.
4. Starter motor spins, but does not engage
a. Check the starter motor for a seized or binding pinion gear.
b. Remove the flywheel inspection plate and check for a damaged ring gear.
5. Engine is difficult to start when Gold
a. Check the battery condition, battery state of charge and starter motor current draw. Re-
place the battery if marginal and the starter motor if the current draw is beyond specifi-
cation. b. Check the battery cable condition. Clean the battery terminals and replace corroded or
damaged cables.
c. Check the fuel system for proper operation. A fuel pump with insufficient fuel pressure
or clogged injectors should be replaced.
d. Check the engine’s tune-up status. Note the tune-up specifications and check for items
such as severely worn spark plugs; adjust or replace as needed. On vehicles with
manually adjusted valve clearances, check for tight valves and adjust to specification.
e. Check for a failed coolant temperature sensor, and replace if out of specification.
f. Check the operation of the engine management systems for fuel and ignition; repair or
replace failed components as necessary.
6. En#ine is ditticutt to start when hot
a. Check the air filter and air intake system. Replace the air filter if it is dirty or contami-
nated. Check the fresh air intake system for restrictions or blockage.
b. Check for loose or deteriorated engine grounds and clean, tighten or replace as
needed.
c. Check for needed maintenance. Inspect tune-up and service related items such as
spark plugs and engine oil condition, and check the operation of the engine fuel and
ignition management system.
Diesel Engines
1. Engine turns over but won’t start
a. Check engine starting procedure and restart engine.
b. Check the glow plug operation and repair or replace as necessary.
c. Check for air in the fuel system or fuel filter and bleed the air as necessary.
d. Check the fuel delivery system and repair or replace as necessary.
e. Check fuel level and add fuel as needed.
f. Check fuel quality. If the fuel is contaminated, drain and flush the fuel tank.
g. Check engine compression. If compression is below specification, the engine may
need to be renewed or replaced.
h. Check the injection pump timing and set to specification.
i. Check the injection pump condition and replace as necessary.
j. Check the fuel nozzle operation and condition or replace as necessary.
2. Engine does
hot turn over when attempting to start
a. Check the battery state of charge and condition. If the dash lights are not visible or
very dim when turning the ignition key on, the battery has either failed internally or
discharged, the battery cables are loose, excessively corroded or damaged, or the al-
ternator has failed or internally shorted, discharging the battery. Charge or replace the
battery, clean or replace the battery cables, and check the alternator output.
b. Check the operation of the neutral safety switch. On automatic transmission vehicles,
try starting the vehicle in both Park and Neutral. On manual transmission vehicles, de-
press the clutch pedal and attempt to start. On some vehicles, these switches can be
adjusted. Make sure the switches or wire connectors are not loose or damaged. Re-
place or adjust the switches as necessary.
c. Check the starter motor, starter solenoid or relay, and starter motor cables and wires.
Check the ground from the engine to the chassis. Make sure the wires are not loose,
damaged, or corroded. If battery voltage is present at the starter relay, try using a re-
mote starter to start the vehicle for test purposes only. Replace any damaged or cor-
roded cables, in addition to replacing any failed components.
d. Check the engine for seizure. If the engine has not been started for a long period of
time, internal parts such as the rings may have rusted to the cylinder walls. The engine
may have suffered internal damage, or could be hydro-locked from ingesting water.
Remove the injectors and carefully attempt to rotate the engine using a suitable
breaker bar and socket on the crankshaft pulley. If the engine is resistant to moving, or
moves slightly and then binds, do not force the engine any further before determining
the cause of the problem.
3. Engine stalls afier starting
a. Check for a restriction in the fuel return line or the return line check valve and repair as
necessary.
b. Check the glow plug operation for turning the glow plugs off too soon and repair as
necessary.
c. Check for incorrect injection pump timing and reset to specification.
d. Test the engine fuel pump and replace if the output is below specification.
e. Check for contaminated or incorrect fuel. Completely flush the fuel system and replace
with fresh fuel.
f. Test the engine’s compression for low compression. If below specification, mechanical
repairs are necessary to repair.
g. Check for air in the fuel. Check fuel tank fuel and fill as needed.
h. Check for a failed injection pump. Replace the pump, making sure to properly set the
pump timing.
TROUBLESHOOiNG 11-7
4. Starter motor spins, but does not engage
a. Check the starter motor for a seized or binding pinion gear.
b. Remove the flywheel inspection plate and check for a damaged ring gear.
Gasoline Engines
1. Engine runs poor/y, hesiiates
a. Check the engine ignition system operation and adjust if possible, or replace defective
parts.
b. Check for restricted fuel injectors and replace as necessary.
c. Check the fuel pump output and delivery. Inspect fuel lines for restrictions. If the fuel
pump pressure is below specification, replace the fuel pump.
d. Check the operation of the engine management system and repair as necessary.
2. Enfline lacks power
a. Check the engine’s tune-up status. Note the tune-up specifications and check for items
such as severely worn spark plugs; adjust or replace as needed. On vehicles with
manually adjusted valve clearances, check for tight valves and adjust to specification.
b. Check the air filter and air intake system. Replace the air filter if it is dirty or contami-
nated. Check the fresh air intake system for restrictions or blockage.
c. Check the operation of the engine fuel and ignition management systems. Check the
sensor operation and wiring. Check for low fuel pump pressure and repair or replace
components as necessary.
d. Check the throttle linkage adjustments. Check to make sure the linkage is fully open-
ing the throttle. Replace any worn or defective bushings or linkages.
e. Check for a restricted exhaust system. Check for bent or crimped exhaust pipes, or in-
ternally restricted mufflers or catalytic converters. Compare inlet and outlet tempera-
tures for the converter or muffler. If the inlet is hot, but outlet cold, the component is
restricted.
f. Check for a loose or defective knock sensor. A loose, improperly torqued or defective
knock sensor will decrease spark advance and reduce power. Replace defective knock
sensors and install using the recommended torque specification.
g. Check for engine mechanical conditions such as low compression, worn piston rings,
worn valves, worn camshafts and related parts. An engine which has severe mechani-
cal wear, or has suffered internal mechanical damage must be rebuilt or replaced to re-
store lost power.
h. Check the engine oil level for being overfilled. Adjust the engine’s oil level, or change
the engine oil and filter, and top off to the correct level.
i. Check for an intake manifold or vacuum hose leak. Replace leaking gaskets or worn
vacuum hoses.
j. Check for dragging brakes and replace or repair as necessary.
k. Check tire air pressure and tire wear. Adjust the pressure to the recommended set-
tings. Check the tire wear for possible alignment problems causing increased rolling
resistance, decreased acceleration and increased fuel usage.
I. Check the octane rating of the fuel used during refilling, and use a higher octane rated
fuel.
3. Poor fuel economy
a. Inspect the air filter and check for any air restrictions going into the air filter housing.
Replace the air filter if it is dirty or contaminated.
b. Check the engine for tune-up and related adjustments. Replace worn ignition parts,
check the engine ignition timing and fuel mixture, and set to specifications if possible.
c. Check the tire size, tire wear, alignment and tire pressure. Large tires create more
rolling resistance, smaller tires require more engine speed to maintain a vehicle’s road
speed. Excessive tire wear can be caused by incorrect tire pressure, incorrect wheel
alignment or a suspension problem. All of these conditions create increased rolling
resistance, causing the engine to work harder to accelerate and maintain a vehicle’s
speed.
d. Inspect the brakes for binding or excessive drag. A sticking brake caliper, overly ad-
justed brake shoe, broken brake shoe return spring, or binding parking brake cable or
linkage can create a significant drag, brake wear and loss of fuel economy. Check the
brake system operation and repair as necessary.
4. Engine runs on (diesels) when turned off
a. Check for idle speed set too high and readjust to specification.
b. Check the operation of the idle control valve, and replace if defective.
c. Check the ignition timing and adjust to recommended settings.
Check for defective
sensors or related components and replace if defective.
d. Check for a vacuum leak at the intake manifold or vacuum hose
and replace defective
gaskets or hoses.
e. Check the engine for excessive carbon build-up in the combustion chamber. Use a
recommended decarbonizing fuel additive or disassemble the cylinder head to remove
the carbon.
f. Check the operation of the engine fuel management system and replace defective sen-
sors or control units.
g. Check the engine operating temperature for overheating and repair as necessary. 5. Engine knocks and pinfls during heavy accele/ation, and on steep hills
a. Check the octane rating of the fuel used during refilling, and use a higher octane rated
fuel.
b. Check the ignition timing and adjust to recommended settings. Check for defective
sensors or related components and replace if defective.
c. Check the engine for excessive carbon build-up in the combustion chamber. Use a
recommended decarbonizing fuel additive or disassemble the cylinder head to remove
the carbon.
d. Check the spark plugs for the correct type, electrode gap and heat range. Replace worn
or damaged spark plugs. For severe or continuous high speed use, install a spark plug
that is one heat range colder.
e. Check the operation of the engine fuel management system and replace defective sen-
sors or control units.
f. Check for a restricted exhaust system. Check for bent or crimped exhaust pipes, or in-
ternally restricted mufflers or catalytic converters. Compare inlet and outlet tempera-
tures for the converter or muffler. If the inlet is hot, but outlet cold, the component is
restricted.
6. Engine atxelerates, but vehicle does not gain speed
a. On manual transmission vehicles, check for causes of a slipping clutch. Refer to the
clutch troubleshooting section for additional information.
b. On automatic transmission vehicles, check for a slipping transmission” Check the
transmission fluid level and condition. If the fluid level is too high, adjust to the cor-
rect level. If the fluid level is low, top off using the recommended fluid type. If the fluid
exhibits a burning odor, the transmission has been slipping internally. Changing the
fluid and filter may help temporarily, however in this situation a transmission may re-
quire overhauling to ensure long-term reliability.
Diesel Engines
1. Engine runs pOOr!y a. Check the injection pump timing and adjust to specification.
b. Check for air in the fuel lines or leaks, and bleed the air from the fuel system.
c. Check the fuel filter, fuel feed and return lines for a restriction and repair as necessary.
d. Check the fuel for contamination, drain and flush the fuel tank and replenish with fresh
fuel.
2. Enfline lacks power
a. Inspect the air intake system and air filter for restrictions and, if necessary, replace the
air filter.
b. Verify the injection pump timing and reset if out of specification.
c. Check the exhaust for an internal restriction and replace failed parts.
d. Check for a restricted fuel filter and, if restricted, replace the filter.
e. Inspect the fuel filler cap vent. When removing the filler cap, listen for excessive hiss-
ing noises indicating a blockage in the fuel filler cap vents, If the filler cap vents are
blocked, replace the cap.
f. Check the fuel system for restrictions and repair as necessary.
g. Check for low engine compression and inspect for external leakage at the glow plugs
or nozzles. If no external leakage is noted, repair or replace the engine.
ENGINE PERFORMANCE TROUBLESHOOTING HINTS When troubleshooting an engine running or performance condition, the mechanical
condition of the engine should be determined before lengthy troubleshooting procedures
are performed.
The engine fuel management systems in fuel injected vehicles rely on electronic sen-
sors to provide information to the engine control unit for precise fuel metering. Unlike
carburetors, which use the incoming air speed to draw fuel through the fuel metering jets
in order to provide a proper fuel-to-air ratio, a fuel injection system provides a specific
amount of fuel which is introduced by the fuel injectors into the intake manifold or intake
port, based on the information provided by electronic sensors.
The sensors monitor the engine’s operating temperature, ambient temperature and the
amount of air entering the engine, engine speed and throttle position to provide informa-
tion to the engine control unit, which, in turn, operates the fuel injectors by electrical
pulses. The sensors provide information to the engine control unit using low voltage
electrical signals. As a result, an unplugged sensor or a poor electrical contact could
cause a poor running condition similar to a failed sensor.
When troubleshooting a fuel related engine condition on fuel injected vehicles, care-
fully inspect the wiring and electrical connectors to the related components. Make sure
the electrical connectors are fully connected, clean and not physically damaged. If neces-
sary, clean the electrical contacts using electrical contact cleaner. The use of cleaning
agents not specifically designed for electrical contacts should not be used, as they could
leave a surface film or damage the insulation of the wiring.
The engine electrical system provides the necessary electrical power to operate the ve-
hicle’s electrical accessories, electronic control units and sensors. Because engine man-
agement systems are sensitive to voltage changes, an alternator which over or under-
charges could cause engine running problems or component failure. Most alternators
utilize internal voltage regulators which cannot be adjusted and must be replaced indi-
vidually or as a unit with the alternator.
II-14 TROUBLESHOOTING
b. Check for low voltage at the bulb socket positive terminal or a poor ground. If voltage
is low, or the ground marginal, trace the wiring to, and check for loose, damaged or
corroded wires and electrical terminals; repair as necessary.
c. Check the light switch operation and replace if necessary.
1. Interior light inoperative
a. Verify the interior light switch location and position(s), and set the switch in the cor-
rect position.
b. Check for battery voltage and ground at the interior light bulb socket. If battery voltage
and ground are present, replace the bulb. If voltage is not present, check the interior
light fuse for battery voltage. If the fuse is missing, replace the fuse. If the fuse has
blown, or if battery voltage is present, refer to the wiring diagram to troubleshoot the
cause for an open or shorted circuit. If ground is not present, check the door switch
contacts and clean or repair as necessary.
2. Interior light works intermittent/y
a. Check the bulb for a damaged filament, and replace if damaged.
b. Check the bulb and bulb socket for corrosion, and clean or replace the bulb and
socket.
c. Check for loose, damaged or corroded wires and electrical terminals; repair as neces-
sary.
d. Check the door and light switch operation, and replace if necessary.
3. Interior light very dim
a. Check the bulb and bulb socket for corrosion, and clean or replace the bulb and
socket.
b. Check for low voltage at the bulb socket positive terminal or a poor ground. If voltage
is low, or the ground marginal, trace the wiring to, and check for loose, damaged or
corroded wires and electrical terminals; repair as necessary.
c. Check the door and light switch operation, and replace if necessary.
1. One brake light inoperative
a. PressPress the brake pedal and check for battery voltage and ground at the brake light
bulb socket. If present, replace the bulb. If either battery voltage or ground is not pre-
sent, refer to the wiring diagram to troubleshoot.
2. Both brake lights inoperative
a. Press the brake pedal and check for battery voltage and grou’nd at the brake light bulb
socket. If present, replace both bulbs. If battery voltage is not present, check the brake
light switch adjustment and adjust as necessary. If the brake light switch is properly
adjusted, and battery voltage or the ground is not present at the bulb sockets, or at the
bulb electrical connector with the brake pedal pressed, refer to the wiring diagram to
troubleshoot the cause of an open circuit.
3. One or both brake lights very dim
a. Press the brake pedal and measure the voltage at the brake light bulb socket. If the
measured voltage is close to the battery voltage, check for a poor ground caused by a
loose, damaged, or corroded wire, terminal, bulb or bulb socket. If the ground is
bolted to a painted surface, it may be necessary to remove the electrical connector and
clean the mounting surface, so the connector mounts on bare metal. If battery voltage
is low, check for a poor connection caused by either a faulty brake light switch, a
loose, damaged, or corroded wire, terminal or electrical connector. Refer to the wiring
diagram to troubleshoot the cause of a voltage drop.
1. Warning light(s) stay on when the engine is started
Ignition, Battery or Alternator Warning light a. Check the alternator output and voltage regulator operation, and replace as necessary.
b. Check the warning light wiring for a shorted wire.
Check Engine Light a. Check the engine for routine maintenance and tune-up status. Note the engine tune-up
specifications and verify the spark plug, air filter and engine oil condition; replace
and/or adjust items as necessary.
b. Check the fuel tank for low fuel level, causing an intermittent lean fuel mixtur
e. Top off fuel tank and reset check engine light.
c. Check for a failed or disconnected engine fuel or ignition component, sensor or con-
trol unit and repair or replace as necessary.
d. Check the intake manifold and vacuum hoses for air leaks and repair as
necessary.
e. Check the engine’s mechanical condition for excessive oil consumption.
Anti-Lock Braking System (ABS) Light a. Check the wheel sensors and sensor rings for debris, and clean as necessary.
b. Check the brake master cylinder for fluid leakage or seal failure and replace as neces-
sary.
c, Check the ABS control unit, pump and proportioning valves for proper operation; re-
place as necessary.
d. Check the sensor wiring at the wheel sensors and the ABS control unit for a loose or
shorted wire, and repair as necessary.
brake Warning Light a. Check the brake fluid level and check for possible leakage from the hydraulic lines and
seals. Top off brake fluid and repair leakage as necessary.
b. Check the brake linings for wear and replace as necessary.
c. Check for a loose or shot-ted brake warning light sensor or wire, and replace or repair
as necessary.
Oil Pressure Warning Light a. Stop the engine immediately. Check the engine oil level and oil filter condition, and
top off or change the oil as necessary.
b. Check the oil pressure sensor wire for being shorted to ground. Disconnect the wire
from the oil pressure sensor and with the ignition in the ON position, but not running,
the oil pressure light should not be working. If the light works with the wire discon-
nected, check the sensor wire for being shorted to ground. Check the wire routing to
make sure the wire is not pinched and check for insulation damage. Repair or replace
the wire as necessary and recheck before starting the engine.
c. Remove the oil pan and check for a clogged oil pick-up tube screen.
d. Check the oil pressure sensor operation by substituting a known good sensor.
e. Check the oil filter for internal restrictions or leaks, and replace as necessary.
WARNING: If the engine is operated with oil pressure below the manufac-
turer’s specification, severe (and costly) engine damage could occur. Low
oil pressure can be caused by excessive internal wear or damage to the en-
gine bearings, oil pressure relief valve, oil pump or oil pump drive mecha-
nism.
Before starting the engine, check for possible causes of rapid oil loss, such as leaking
oil lines or a loose, damaged, restricted, or leaking oil filter or oil pressure sensor. If the
engine oil level and condition are acceptable, measure the engine’s oil pressure using a
pressure gauge, or determine the cause for the oil pressure warning light to function
when the engine is running, before operating the engine for an extended period of time.
Another symptom of operating an engine with low oil pressure is the presence of severe
knocking and tapping noises.
Parking Brake Warning Light a. Check the brake release mechanism and verify the parking brake has been fully re-
leased.
b. CheckCheck the parking brake light switch for looseness or misalignment.
c. CheckCheck for a damaged switch or a loose or shorted brake light switch wire, and
replace or repair as necessary.
2. Warning light(s) flickers on and off when driving
Ignition, Battery or Alternator Warning Light a. Check the alternator output and voltage regulator operation. An intermittent condition
may indicate worn brushes, an internal short, or a defective voltage regulator. Replace
the alternator or failed component.
b. Check the warning light wiring for a shorted, pinched or damaged wire and repair as
necessary.
Check Engine Light a. Check the engine for required maintenance and tune-up status. Verify engine tune-up
specifications, as well as spark plug, air filter and engine oil condition; replace and/or
adjust items as necessary.
b. Check the fuel tank for low fuel level causing an intermittent lean fuel mixture. Top off
fuel tank and reset check engine light.
c. Check for an intermittent failure or partially disconnected engine fuel and ignition
component, sensor or control unit; repair or replace as necessary.
d. Check the intake manifold and vacuum hoses for air leaks, and repair as necessary.
e. Check the warning light wiring for a shorted, pinched or damaged wire and repair as
necessary.
Anti-Lock Braking System (ABS) Light a. Check the wheel sensors and sensor rings for debris, and clean as necessary.
b. Check the brake master cylinder for fluid leakage or seal failure and replace as neces-
sary.
c. Check the ABS control unit, pump and proportioning valves for proper operation, and
replace as necessary.
GLOSSARY 11-17
AIR/FUEL RATIO: The ratio of air-to-gasoline by weight in the fuel mixture
drawn into the engine.
AIR INJECTION: One method of reducing harmful exhaust emissions by in-
jecting air into each of the exhaust ports of an engine. The fresh air entering
the hot exhaust manifold causes any remaining fuel to be burned before it can
exit the tailpipe.
ALTERNATOR: A device which produces AC (alternating current) which is
converted to DC (direct current) to charge the car battery.
AMMETER: An instrument, calibrated in amperes, used to measure the flow
of an electrical current in a circuit. Ammeters are always connected in series
with the circuit being tested.
AMPERE: The rate of flow of electrical current present when one volt of elec-
trical pressure is applied against one ohm of electrical resistance.
ANALOG COMPUTER: Any microprocessor that uses similar (analogous)
electrical signals to make its calculations.
ARMATURE: A laminated, soft iron core wrapped by a wire that converts elec-
trical energy to mechanical energy as in a motor or relay. When rotated in
a magnetic field, it changes mechanical energy into electrical energy as in a
generator.
ATMOSPHERIC PRESSURE: The pressure on the Earth’s surface caused
by the weight of the air in the atmosphere. At sea level, this pressure is 14.7
psi at 32°F (101 kPa at OOC).
ATOMIZATION: The breaking down of a liquid into a fine mist that can be
suspended in air.
AXIAL PLAY: Movement parallel to a shaft or bearing bore.
BACKFIRE: The sudden combustion of gases in the intake or exhaust sys-
tem that results in a loud explosion.
BACKLASH: The clearance or play between two parts, such as meshed gears.
BACKPRESSURE: Restrictions in the exhaust system that slow the exit of
exhaust gases from the combustion chamber.
BAKELITE[reg]: A heat resistant, plastic insulator material commonly used
in printed circuit boards and transistorized components.
BALL BEARING: A bearingmade up of hardened inner and outer races be-
tween which hardened steel’balls roll.
BALLAST RESISTOR: A resistor in the primary ignition circuit that lowers
voltage after the engine is started to reduce wear on ignition components.
BEARING: A friction reducing, supportive device usually located between a
stationary part and a moving part.
BI-METAL TEMPERATURE SENSOR: Anv sensor or switch made of two
dissimilar types of metal that bend when heated or cooled due to the different
expansion rates of the alloys. These types of sensors usually function as an
on/off switch. BLOW-BY: Combustion gases, composed of water vapor and unburned fuel,
that leak past the piston rings into the crankcase during normal engine oper-
ation. These gases are removed by the PCV system to prevent the buildup of
harmful acids in the crankcase.
BRAKE PAD: A brake shoe and lining assembly used with disc brakes.
BRAKE SHOE: The backing for the brake lining. The term is, however, usu-
ally applied to the assembly of the brake backing and lining.
BUSHING: A liner, usually removable, for a bearing; an anti-friction liner used
in place of a bearing.
CALIPER: A hydraulically activated device in a disc brake system, which is
mounted straddling the brake rotor (disc). The caliper contains at least one
piston and two brake pads. Hydraulic pressure on the piston(s) forces the pads
against the rotor.
CAMSHAFT: A shaft in the engine on which are the lobes (cams) which op-
erate the valves. The camshaft is driven by the crankshaft, via a belt, chain or
gears, at one half the crankshaft speed.
CAPACITOR: A device which stores an electrical charge.
CARBON MONOXIDE (CO): A colorless, odorless gas given off as a nor-
mal byproduct of combustion. It is poisonous and extremely dangerous in con-
fined areas, building up slowly to toxic levels without warning if adequate ven-
tilation is not available.
CARBURETOR: A device, usually mounted on the intake manifold of an en-
gine, which mixes the air and fuel in the proper proportion to allow even com-
bustion
CATALYTIC CONVERTER: A device installed in the exhaust system, like a
muffler, that converts harmful byproducts of combustion into carbon dioxide
and water vapor by means of a heat-producing chemical reaction.
CENTRIFUGAL ADVANCE: A mechanical method of advancing the spark
timing by using flyweights in the distributor that react to centrifugal force gen-
erated by the distributor shaft rotation.
CHECK VALVE: Any one-way valve installed to permit the flow of air, fuel or
vacuum in one direction only.
CHOKE: The valve/plate that restricts the amount of air entering an engine on
the induction stroke, thereby enriching the air:fuel ratio.
CIRCUIT: Any unbroken path through which an electrical current can flow.
Also used to describe fuel flow in some instances.
CIRCUIT BREAKER: A switch which protects an electrical circuit from
overload by opening the circuit when the current flow exceeds a pre-
determined level. Some circuit breakers must be reset manually, while most
reset automatically.
COIL (IGNITION): Part of the ignition system that boosts the relatively low
voltage supplied by the car’s electrical system to the high voltage required to
fire the spark plugs.
GLOSSARY 1149
GENERATOR: A device which produces direct current (DC) necessary to
charge the battery. OVERHEAD CAMSHAFT (OHC): An engine configuration in which the
camshaft is mounted on top of the cylinder head and operates the valve either
directly or by means of rocker arms.
HEAT RANGE: A term used to describe the ability of a spark plug to carry
away heat. Plugs with longer nosed insulators take longer to carry heat off
effectively.
HUB: The center part of a wheel or gear.
HYDROCARBON (HC): Any chemical compound made up of hydrogen
and carbon. A major pollutant formed by the engine as a by-product of
combustion.
HYDROMETER: An instrument used to measure the specific gravity of a so-
lution.
INCH POUND (inch Ibs.; sometimes in. lb. or in. Ibs.): One twelfth
.
of a foot pound.
INDUCTION: A means of transferring electrical energy in the form of a mag-
netic field. Principle used in the ignition coil to increase voltage.
INJECTOR: A device which receives metered fuel under relatively low pres-
sure and is activated to inject the fuel into the engine under relatively high
pressure at a predetermined time.
INPUT SHAFT: The shaft to which torque is applied, usually carrying the dri-
ving gear or gears.
INTAKE MANIFOLD: A casting of passages or pipes used to conduct air or
a fuel/air mixture to the cylinders.
JOURNAL: The bearing surface within which a shaft operates.
KEY: A small block usually fitted in a notch between a shaft and a hub to pre-
vent slippage of the two parts.
MANIFOLD: A casting of passages or set of pipes which connect the cylin-
ders to an inlet or outlet source.
MASTER CYLINDER: The primary fluid pressurizing device in a hydraulic
system. In automotive use, it is found in brake and hydraulic clutch systems
and is pedal activated, either directly or, in a power brake system, through the
power booster.
MODULE: Electronic control unit, amplifier or igniter of solid state or inte-
grated design which controls the current flow in the ignition primary circuit
based on input from the pick-up coil. When the module opens the primary cir-
cuit, high secondary voltage is induced in the coil.
NEEDLE BEARING: A bearing which consists of a number (usually a large
number) of long, thin rollers.
OHM: The unit used to measure the resistance of conductor-to-electrical flow.
One ohm is the amount of resistance that limits current flow to one ampere in
a circuit with one volt of pressure.
OHMMETER: An instrument used for measuring the resistance, in ohms, in
an electrical circuit.
OUTPUT SHAFT: The shaft which transmits torque from a device, such as a
transmission. OVERHEAD VALVE (OHV): An engine configuration in which all of the
valves are located in the cylinder head
and the camshaft is located in the cylin-
der block. The camshaft operates the valves via lifters and pushrods.
OXIDES OF NITROGEN (NOx): Chemical compounds of nitrogen produced
as a byproduct of combustion. They combine with hydrocarbons to produce
smog.
OXYGEN SENSOR: Used with a feedback system to sense the presence of
oxygen in the exhaust gas and signal the computer which can use the voltage
signal to determine engine operating efficiency and adjust the air/fuel ratio.
PINION: The smaller of two gears. The rear axle pinion drives the ring gear
which transmits motion to the axle shafts.
PISTON RING: An open-ended ring which fits into a groove on the outer di-
ameter of the piston. Its chief function is to form a seal between the piston and
cylinder wall. Most automotive pistons have three rings: two for compression
sealing; one for oil sealing.
PRELOAD: A predetermined load placed on a bearing during assembly or by
adjustment.
PRESS FIT: The mating of two parts under pressure, due to the inner diam-
eter of one being smaller than the outer diameter of the other, or vice versa;
an interference fit.
PRIMARY CIRCUIT: The low voltage side of the ignition system which con-
sists of the ignition switch, ballast resistor or resistance wire, bypass, coil,
electronic control unit and pick-up coil as well as the connecting wires and
harnesses.
RACE: The surface on the inner or otiter ring of a bearing on which the balls,
needles or rollers move.
REGULATOR: A device which maintains the amperage and/or voltage levels
of a circuit at predetermined values.
RELAY: A switch which automatically opens and/or closes a circuit.
RESISTANCE: The opposition to the flow of current through a circuit or elec-
trical device, and is measured in ohms. Resistance is equal to the voltage di-
vided by the amperage.
RESISTOR: A device, usually made of wire, which offers a preset amount of
resistance in an electrical circuit.
RING GEAR: The name given to a ring-shaped gear attached to a differential
case, or affixed to a flywheel or as part of a planetary gear set.
ROLLER BEARING: A bearing made up of hardened inner and outer races
between which hardened steel rollers move.
ROTOR: (1.) The disc-shaped part of a disc brake assembly, upon which the
brake pads bear; also called, brake disc. (2.) The device mounted atop the dis-
tributor shaft, which passes current to the distributor cap tower contacts.
II-20 GLOSSARY
SECONDARY CIRCUIT: The high voltage side of the ignition system, usu-
ally above 20,000 volts. The secondary includes the ignition coil, coil wire,
distributor cap and rotor, spark plug wires and spark plugs.
SENDING UNIT: A mechanical, electrical, hydraulic or electromagnetic de-
vice which transmits information to a gauge.
SENSOR: Any device designed to measure engine operating conditions or
ambient pressures and temperatures. Usually electronic in nature and designed
to send a voltage signal to an on-board computer, some sensors may oper-
ate as a simple on/off switch or they may provide a variable voltage signal
(like a potentiometer) as conditions or measured parameters change.
SHIM: Spacers of precise, predetermined thickness used between parts to es-
tablish a proper working relationship.
SLAVE CYLINDER: In automotive use, a device in the hydraulic clutch sys-
tem which is activated by hydraulic force, disengaging the clutch.
SOLENOID: An electrically operated, magnetic switching device.
SPARK PLUG: A device screwed into the combustion chamber of a spark ig-
nition engine. The basic construction is a conductive core inside of a ceramic
insulator, mounted in an outer conductive base. An electrical charge from the
spark plug wire travels along the conductive core and jumps a preset air gap
to a grounding point or points at the end of the conductive base. The resul-
tant spark ignites the fuel/air mixture in the combustion chamber.
SPLINES: Ridges machined or cast onto the outer diameter of a shaft or in-
ner diameter of a bore to enable parts to mate without rotation.
TACHOMETER: A device used to measure the rotary speed of an engine,
shaft, gear, etc., usually in rotations per minute.
THERMOSTAT: A valve, located in the cooling system of an engine, which
is closed when cold and opens gradually in response to engine heating, con-
trolling the temperature of the coolant and rate of coolant flow.
TOP DEAD CENTER (TDC): The point at which the piston reaches the top
of its travel on the compression stroke.
TORQUE: Measurement of turning or twisting force, expressed as foot-pounds
or inch-pounds.
TORQUE CONVERTER: A turbine used to transmit power from a driving
member to a driven member via hydraulic action, providing changes in drive
ratio and torque. In automotive use, it links the driveplate at the rear of the en-
gine to the automatic transmission. TRANSDUCER: A device that changes energy from one form to another. For
example, a transducer in a microphone changes sound energy to electrical en-
ergy. In automotive air-conditioning controls used in automatic temperature
systems, a transducer changes an electrical signal to a vacuum signal, which
operates mechanical doors.
TRANSISTOR: A semi-conductor component which can be actuated by a
small voltage to perform an electrical switching function.
TUNE-UP: A regular maintenance function, usually associated with the re-
placement and adjustment of parts and components in the electrical and fuel
systems of a vehicle for the purpose of attaining optimum performance.
TURBOCHARGER: An exhaust driven pump which compresses intake air
and forces it into the combustion chambers at higher than atmospheric pres-
sures The increased air pressure allows more fuel to be burned and results
in increased horsepower being produced.
.
VACUUM ADVANCE: A device which advances the ignition timing in re-
sponse to increased engine vacuum.
VACUUM GAUGE: An instrument used for measuring the existing vacuum
in a vacuum circuit or chamber. The unit of measure is inches (of mercury in
a barometer).
VALVE: Devices that can open or close fluid passages in a hydraulic system
and are used for directing fluid flow and controlling pressure.
VALVE CLEARANCE: The measured gap between the end of the valve stem
and the rocker arm, cam lobe or follower that activates the valve.
VISCOSITY: The ability of a fluid to flow. The lower the viscosity rating, the
easier the fluid will flow. 10 weight motor oil will flow much easier than 40
weight motor oil.
VOLTMETER: An instrument used for measuring electrical force in units
called volts. Voltmeters are always connected parallel with the circuit being
tested.
WHEEL CYLINDER: Found in the automotive drum brake assembly, it is a
device, actuated by hydraulic pressure, which, through internal pistons, pushes
the brake shoes outward against the drums.
MASTER INDEX 11-23
GENERALINFORMAITON 3-65
INSPECTION 3-65
REFINISHING 3-67
ENGINE FAN 3-19
REMOVAL & INSTALLATION 3-19
ENGINE MECHANICAL 3-1
ENGINE OVERHAUL TIPS 3-58
CLEANING 3-58
OVERHAUL TIPS 3-58
REPAIRING DAMAGEDTHREADS 3-59
TOOLS 3-58
ENGINE PREPARATION 3-59
ASSEMBLY 3-64
DISASSEMBLY 3-60
INSPECTION 3-
REFINISHING & REPAIRING 3-63
ENGINE RECONDITIONING 3-57
ENGINE START-UP AND BREAK-IN
3-69
BREAKING IT IN 3-69
KEEP IT MAINTAINED 3-69
STARTING THE ENGINE 3-69
ENGINE 'l-33
OIL& FILTER CHANGE 1-34
OILLEVELCHECK 1-33
ENGINE 3-1
REMOVAL&INSTALLATION 3-l
ENGlNECONTROLUNIT/POWERTRAINCONTROLMODULE(ECU/PCM)
4-7
OPERATION 4-7
REMOVAL&INSTALLATION 4-7
ENGINECOOLANTTEMPERATURESENSOR
4-10
OPERATION 4-10
REMOVAL&INSTALLATION 4-10
TESTING 4-10
ENGINECOOLANTTEMPERATURESENDING
UNIT 2-11
REMOVAL&INSTALLATION 2-11
TESTING 2-11
ENGINE IDENTIFICATION NUMBER l-10
ENTERTAINMENT SYSTEMS 6-14
EVAPORATIVECANISTER I-16
SERVICING 1-16
' EVAPORATIVEEMISSIONCONTROLS 4-2
COMPONENTTESTING 4-3
OPERATION 4-2
REMOVAL&INSTALLATION 4-4
EXHAUST MANIFOLD 3-14
REMOVAL & INSTALLATION 3-14
EXHAUST SYSTEM 3-55
EXHAUSTGASRECIRCULATION SYSTEM
4-5
COMPONENTTESTING 4-5
OPERATION 4-5
REMOVAL&INSTALLATION 4-6
EXTERIOR 1 O-2
FASTENERS, MEASUREMENTS AND CONVERSIONS 1-6
. FENDERS 10-4
REMOVAL &INSTALLATION IO-4
FIRING ORDERS 2-7
FLASHERS 6-28
REPLACEMENT 6-28
FLOOR CONSOLE IO-6
REMOVAL& INSTALLATION IO-6 1
FLUID PAN 7-10
FLUID DISPOSAL 1-33
FLUIDS AND LUBRICANTS 1-33
FLYWHEEVDRIVEPLATE 3-55
REMOVAL & INSTALLATION 3-55
FRONT CRANKSHAFT SEAL 3-48
REMOVAL & INSTALLATION 3-48
FRONT SUSPENSION 8-4 FRONTWHEELDRIVEMODELS 1-44
FUELANDENGINEOILRECOMMENDATIONS 1-33
ENGINEOIL l-33
FUEL 1-33
OPERATION IN FOREIGN COUNTRIES
1-33
FUEL LINE FITTINGS 5-2
REMOVAL&INSTALLATION 5-2
FUEL RAIL AND INJECTORS(S)
5-4
REMOVAL &INSTALLATION 5-4
TESTING 5-8
FUELSYSTEM SERVICE PRECAUTIONS 5-3
FUELFILTER 1-15
REMOVAL&INSTALLATION l-15
FUEL LINES AND FITTINGS 5-2
FUELPRESSUREREGULATOR 5-9
REMOVAL & INSTALLATION 5-9
FUEL TANK 5-10
FUSES 6-27
REPLACEMENT 6-27
FUSIBLE LINKS 6-27 #
RESETTING AND/OR REPLACEMENT 6-28
GAUGES 6-18
REMOVAL & INSTALLATION 6-18
GENERAL INFORMATION 5-3
GENERAL INFORMATION 6-7
DISARMING 6-7
REARMING 6-7
SERVICE PRECAUTIONS 6-7
GENERAL INFORMATION 9-24
PRECAUTIONS 9-24
GENERALINFORMATION 2-10
GENERALINFORMATION 2-2
CYLINDER DROPTEST 2-2
SECONDARYSPARKTEST 2-2
GENERALINFORMATION 2-5
GENERALINFORMATION 2-8
REMOVAL &INSTALLATION 2-9'
TESTING 2-8
GENERALINFORMATION 4-26
CHECKENGlNE/MALFUNCTlONlNDlCATOR LIGHT 4-26
SERVICE PRECAUTIONS 4-26
GENERALINFORMATION 4-27
G-SENSOR 9-29
REMOVAL &INSTALLATION 9-29
HALFSHAFTS 7-13
HALFSHAFTS 7-3
CV-JOINTS OVERHAUL 7-5
REMOVAL&INSTALLATION 7-3
HATCH/TAILGATE/TRUNKLID LOCKCYLINDER lo-10
REMOVAL & INSTALLATION IO-IO
HATCH IO-3
ALIGNMENT IO-3
REMOVAL & INSTALLATION IO-3
HEADLIGHT SWITCH 6-19
REMOVAL 81 INSTALLATION 6-19
HEADLIGHTS 6-19
AIMING THE HEADLIGHTS 6-20
REMOVAL& INSTALLATION 6-19
HEATER CORE 6-9
REMOVAL&INSTALLATION 6-9
HEATING AND AIR CONDITIONING 6-7
HOOD IO-2
ALIGNMENT IO-3
REMOVAL & INSTALLATION IO-2
HOSES I-20
INSPECTION I-20
REMOVAL&INSTALLATION I-21
HOW TO USE THIS BOOK 1-2
HUB & BEARINGS 8-25